In the past dart detection and location systems and methods have relied upon an identifiable electromagnetic signal or signals which is transmitted between two antennae, one of which is one of a plurality of electrically isolated areas of the target and the other is a conventional wire or rod. One of these antennae is electrically connected to a signal generating or transmitting (transmit) circuit, and other of these antennae is connected to a signal detecting (or receiving) circuit.
Essential to these prior methods and systems is that each target area must be rendered electrically conductive and must be electrically insulated from adjacent target areas so that a dart or other such missile which becomes embedded in the conductive target area material becomes electrically connected to a circuit unique to that target area.
When a dart becomes embedded into the target, it forms an extension to the antenna so formed by the target area, whether it be transmitting or receiving, and thereby improves the efficiency of the electromagnetic link and results in an increase of the identifiable signal at the target area, by which means the presence of the missile may be detected.
This arrangement suffers from the disadvantages that the target assembly is necessarily complex, suffering from the need to maintain a high degree of uniformity of conductivity of the target areas, a high degree of integrity of the electrical connections and a high degree of integrity of electrical isolation between the discrete target areas, requiring the use of expensive, specially constructed targets. Moreover, the fibers or other material which form the target area into which the missile is embedded must essentially be made conductive to the flow of electricity which has many disadvantages.
Another disadvantage is that these prior methods and systems cannot generally be used with missiles in which the portion of the missile which embeds into the conductive material of the target area is itself electrically nonconductive. In this case there would be no conductive link between any conductive material which may be in the missile body and which might function as an antenna and the conductive material of the target area. Thus, the prior methods and systems are generally inoperative were plastic or other nonconductive soft tipped darts are used. Some jurisdictions have mandated the use of soft tipped darts and, even where they are not mandated, they may be preferred from the safety standpoint.